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Cement Foundation: SMALL STRUCTURES such as brick planters and masonry walls must be built on strip foundations. These consist of a trench filled with a layer of compacted rubble (which comprises broken stones or bricks) topped with fresh cement.
The foundation is built wider than the wall, so that the weight of the Wall is spread out at an angle of 45 degrees ("the angle of dispersion") from its base into the foundation and on into the subsoil. To gauge the correct width of foundation for a given Wall width you should, as a rule of thumb, allow twice the width of the masonry.
The depth of the cement foundation depends on the height and thickness of the Wall and on the condition of the soil, but in general it should be half as deep as it is wide, and project beyond the ends of the Wall by half the width of the masonry. For example, a Wall over six courses of bricks high would require a trench about I6in deep.
The resulting cement, produced from the formerly discarded grappiers, was of much higher quality than that obtained from the unsintered material. This fact was firmly established by the English cement manufacturer L. C. Johnson in 1845, and the term "portland cement" has since been applied solely to the cement made from the sintered material. This period marks the real beginning of the portland cement industry.
The most important modern uses of grout are to fill the joints in concrete dams and to seal and stabilize the foundations of all types of dams. Other uses of grout include the filling of small spaces between the base plate of heavy machinery and its concrete foundation, filling cavities behind tunnel linings, and filling voids in preplaced particles of coarse aggregate.
The term "grout" also includes chemical formulations that do not contain portland cement. A chemical grout, which is used for the same purposes as neat cement grout, can fill voids that are too small to permit the entrance of portland cement particles. |
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